text: Both players could make their Rovers debut at Accrington on Saturday.
  Mason, 19, a junior player with Real Madrid who then featured for Blackburn and Southampton youth teams, is yet to make a first-team appearance for Villa.
  Houghton, 20, an academy player at Chelsea, had loan spells with Gillingham and Plymouth last term.
  Meanwhile, Chelsea goalkeeper Matej Delac, 24, has joined Belgian side Royal Excel Mouscron on a season-long loan, while 19-year-old midfielder Bekanty Victorien Angban will spend the coming campaign on loan at Granada in La Liga.
  Find all the latest football transfers on our dedicated page.
target: Doncaster Rovers have signed Chelsea midfielder Jordan Houghton and Aston Villa defender Niall Mason on loan until January.